=over

=item IO::Handle->format_line_break_characters EXPR

=item $FORMAT_LINE_BREAK_CHARACTERS

=item $:
X<$:> X<FORMAT_LINE_BREAK_CHARACTERS>

The current set of characters after which a string may be broken to
fill continuation fields (starting with C<^>) in a format.  The default is
S<" \n-">, to break on a space, newline, or a hyphen.

You cannot call C<format_line_break_characters()> on a handle, only as
a static method.  See L<IO::Handle|IO::Handle>.

Mnemonic: a "colon" in poetry is a part of a line.

=back